1. Field of the Invention
The present invention relates to a backlight module and a liquid crystal display including the backlight module.
2. Description of Prior Art
FIG. 1 is a schematic view of a conventional backlight module 100 using a point light source as a side light source. Referring to FIG. 1, when the point light source 102 (for example a light emitting diode) is used as the side light source, the front end of the light guide plate 104 may generate a hot spot HS and a dark spot DS distributed alternately base on the light emitting characteristic of the point light source 102. Therefore, there is a need to reserve a large light mixing region 105 for uniformly diffusing the light energy, and this may reduce the effective uniformity light emitting region of the light guide plate 104 greatly. To solve the problem, as shown in FIG. 2, in another conventional backlight module 200 design, the microstructure 106 may be disposed on the light incident side of the light guide plate 104 and the light beam through the microstructure 106 may increase a deflection angle of the incident light beam, so as to form the hot spot HS on the region of the light guide plate adjacent to the light incident side and thus effectively reduce the area of the light mixing region 105. Referring to FIG. 1, the side light beam I may be originally reflected into the light guide plate 104 by the side of the light guide plate 104a, and referring to FIG. 2, after the deflection angle of the incident light beam is increased by the light diffusing effect of the microstructure 106, a part of the side light beam I′ may be refracted out of the light guide plate 104, so as to reduce the light utilization efficiency. In addition, when the part of the side light beam I′ refracted out of the light guide plate 104 may encounter outside structure, for example the frame 108 having reflective material with the matt surface, the part of the side light beam I′ may be reflected by the surface of the frame 108, so as to form the obvious side hot spot 112.